CODEWITHSUNDEEP
typescript
bingles
bingles

Reputation: 12223

TypeScript: Is it possible to define a class that creates an instance of a function?

In TypeScript is it possible for a class to be a constructor of a function instance? I envision something like:

class SomeThing {
    (name: string) {
       // do something with name
    }
}

let thing = new SomeThing();
thing('John Doe');

Upvotes: 2

Views: 34

Answers (1)

Ryan Cavanaugh
Ryan Cavanaugh

Reputation: 221352

It's technically possible (it requires some hacks I'm not going to write here) but you really don't want to do this; here's why.

The new operator creates a new object (not function) whose __proto__ is the prototype of the operand. This means you can't possibly have a callable thing returned by the new operator, unless you explicitly return something else out of the constructor.

But if you return something else out of the constructor, then thing instanceof SomeThing is going to be false, and you're not going to be able to use prototype methods of the class from thing. So at that point it's not really behaving like a class at all, and you're better off just having a factory function, which can do whatever it wants.

Upvotes: 4

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